By Vint Cerf, Chief Internet Evangelist, Google
August 6 2019: When Google Science Fair launched last fall, we challenged students to channel their curiosity and ingenuity to invent, code or build a solution to a problem they’re passionate about. Thousands of students participated, and this weekend we welcomed our 24 finalists—from 14 countries around the world—to explore Google’s headquarters to reveal the winners.
These changemakers tackled issues across sustainability, healthcare, and accessibility. We saw impressive entries that used a variety of STEM disciplines—from using AI to help detect disease in plants to finding new ways to diagnose heart disease.
The winners
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Indian team's achievement: Averrhoa Bilimbi - A Natural Coagulant for Rubber Latex
Rubber products are plays an significant role in the modern world.The world rubber market was crushed by the rapid development of the more efficient rubber plantations of South east Asia and america. However, the prospects of developing plantations did not begin on a high note.
A common fruit seen in our area named Bilimbi [Averrhoa Bilimbi] is found in abundance and generally considered as weed fruit, is also known to have medicinal value in ancient Indian traditional system. To check its potential in other areas we have tried an extract from this fruit which acts as a natural non- corrosive coagulating agent for rubber latex.
1litre of Bilimbi extract is prepared by grinding 1kg of Bilimbi fruit with 100ml of water. To coagulate 2litres of Rubber Latex, we have to add 60ml of filtered Bilimbi extract. It took 10hours to coagulate. We observed that using our method, rubber latex coagulated 6hours faster than the current method of rubber latex mixed with formic acid .The current method which is produced synthetically in the industries using toxic chemicals such as methanol, carbon monoxide and sodium methoxide.
Rubber Latex is a colloid in which rubber particles dispersed in water solution and are negatively charged. Effectiveness of the acid to coagulate depends on the number of positive ions. While Bilimbi extract is added to the rubber latex a physical reaction takes place by neutralizing the negative colloidal particles in the rubber latex and makes them bigger particles. If the rubber latex exceeds 10-6m, the particles settle down and the coagulation takes place.
Qualitative and quantitative analysis of bilimbi extract indicated the presence of oxalic acid and acetic acid. When the rubber latex is coagulated with both oxalic and acetic acid together the coagulation period reduced into minimum which is almost equivalent to Bilimbi extract. As oxalic acid contains 2 replaceable hydrogen atoms and acetic acid contains one replaceable hydrogen atom there may be the formation of 3 hydrogen ions, which can coagulate faster than formic acid which produces only 1 H+ion. Oxalic acid may also be responsible for Diels Alder reaction with rubber particals.
We have conducted Physiochemical tests like anti bacterial, anti fungal, pH and TLC of bilimbi extract. The pH of the extract is 1.31.As it has anti microbial property the rubber sheet cannot be infected by microbes easily. Tests like viscosity, pH, element test and surface tension tests were conducted
Tensile, hardness, elasticity and the density of both the rubber sheets are measured without any significant difference. Therefore we can infer that our natural coagulant used for rubber coagulation is equally good.
Also, Formic acid is highly corrosive and more expensive than bilimbi extract which is easily available in bulk, eco friendly, non toxic, natural alternative. Fuller details and photos here